A phase I/Ib study of OTSGC-A24 combined peptide vaccine in advanced gastric cancer

Raghav Sundar, Sun Young Rha, Hiroki Yamaue, Masahiro Katsuda, Koji Kono, Hyo Song Kim, Chan Kim, Kousaku Mimura, Ley Fang Kua, Wei Peng Yong

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25 Citations (Scopus)


Background: We conducted a phase I/Ib, open-label, single-arm trial to assess the safety, tolerability and optimal scheduling regimen of OTSGC-A24 cancer vaccine in patients with advanced gastric cancer. Methods: Patients with advanced gastric cancer with HLA-A*24:02 haplotype were included in this study. OTSGC-A24 was administered at 1 mg in 3-weekly (3w), 2-weekly (2w), and weekly (1w) cohorts to evaluate the safety, immunological response and schedule. Based on the highest specific cytotoxic T lymphocyte (CTL) induction rate at 4 weeks, using the ELISPOT test, cohorts were expanded to define the optimal dosing schedule for OTSGC-A24. Results: In this study, 24 advanced gastric cancer patients with HLA-A*24:02 haplotype were enrolled and treated in 3 cohorts (3w cohort: 3; 2w cohort: 11 and 1w cohort: 10 patients). The most common adverse events were decreased appetite (29%), diarrhea (21%), myalgia (25%). The most common treatment-related adverse event was injection site erythema (25%). No dose-limiting toxicities were observed in any cohort and OTSGC-A24 was well tolerated. Positive CTL responses after vaccination were observed in 15 patients (75%) at 4 weeks: 3w cohort (33%), 2w cohort (88%), 1w cohort (78%). At 12 weeks, 18 patients had responded (90%); 3w cohort (100%), 2w cohort (100%), 1w cohort (78%). The best radiological was stable disease (40%). Median progression free survival was 1.7 months (95% CI: 1.4 to 3.5) and median overall survival was 5.7 months (95% CI 3.8 to 8.6). Conclusions: OTSGC-A24 combined peptide cancer vaccine was well tolerated. Significant responses in CTL were observed and the recommended phase 2 dose is 1 mg OTSGC-A24 sub-cutaneous, every 2 weeks. Although no radiological response was observed, a respectable overall survival was achieved, consistent with other immunotherapy agents being investigated in gastric cancer.

Original languageEnglish
Article number332
JournalBMC cancer
Issue number1
Publication statusPublished - 2018 Mar 27

Bibliographical note

Funding Information:
HY has received a research grant from Oncotherapy Science. YWP has received a research grant from Oncotherapy Science. None of the other authors have any conflict of interests to declare.

Publisher Copyright:
© 2018 The Author(s).

All Science Journal Classification (ASJC) codes

  • Genetics
  • Oncology
  • Cancer Research


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